This is my last try on the leaves.
It needs much much more tests.And i will leave it at this for now.
When i saw this a different thing came to my mind. That is in the other post
*I used leaning effect,powerfractal displacement restricted with a surface layer and a animated transform input.
*I made the tree in 3 parts. It does have a separate trunk,branches and one high poly leaf that is populated on the branches.
The leaf is only populated on the upper side of the branches.
*The populated leaf and the branches are displaced with different nodes and values.The trunk is not animated(not much seen anyway).
The vanishing of some leaves is much less then i anticipated.
The thing about the outward displacing when mesh displacement is used that Matt explaned is to me much more clear here.
The leaves doesn't displace in the normal directions.They look like they are growing smaller and bigger mostly.
I think when this kinda same setup would be used with real displacement (Raytrace OFF) the look might be at least on the leaves much better then this.